I've been chasing an idle issue around for a long time. I removed the Comp Cams XE270's and put the stock cams back in. The idle issue is still there, but it doesn't stall. This allowed me to duplicate the problem and data log it.
Here is part of the problem. From idle, if I blip the throttle (first event) and rev to 2500 rpm (blue line) the dashpot (orange line) jumps and the rpm falls in a controlled manner with the dashpot. However if I blip and rev to 1500 rpm (second event) the rpm drops uncontrolled, almost stalls and recovers. The idle hunts. The maroon line is spark.
With the large cams the second event would stall, but it does not with the stock cams.
So I've adjusted the rpm error for idle control and the dashpot preposition. Neither seemed to help. I'm going to focus on the dashpot preposition now, but I'm looking for ideas.
Here is part of the problem. From idle, if I blip the throttle (first event) and rev to 2500 rpm (blue line) the dashpot (orange line) jumps and the rpm falls in a controlled manner with the dashpot. However if I blip and rev to 1500 rpm (second event) the rpm drops uncontrolled, almost stalls and recovers. The idle hunts. The maroon line is spark.
With the large cams the second event would stall, but it does not with the stock cams.
So I've adjusted the rpm error for idle control and the dashpot preposition. Neither seemed to help. I'm going to focus on the dashpot preposition now, but I'm looking for ideas.